How to deploy a high-availability architecture in Linux

With the advent of the big data era, more and more companies and organizations are beginning to use Linux operating systems as their server platforms. In order to ensure the availability and stability of applications, high-availability architecture has become an indispensable part of Linux servers. This article will introduce how to deploy a high-availability architecture in Linux.

What is a high availability architecture?

High Availability (HA) refers to a system architecture that can continue to provide services when the system fails. HA can be implemented through a variety of technologies, such as load balancing, redundant backup, failover, etc. For enterprise-level applications, maintaining high availability is critical because it ensures that the application can continue to function normally in the event of unexpected circumstances.

Steps to deploy a high-availability architecture in Linux

1. Network planning

First, you need to plan the network. To ensure high availability, each node in the cluster should be assigned an independent IP address and combined into a virtual IP address. In addition, network storage needs to be configured for the cluster to share data between nodes.

2. Install software

Before installing the software, install the necessary software packages on each node, such as heartbeat, corosync and pcs packages. It can be installed on CentOS using the following command:

sudo yum install corosync pcs pacemaker resource-agents

3. Configure Corosync and Heartbeat

Next, Corosync and Heartbeat need to be configured to enable communication between the two nodes . This is one of the key steps to ensure high availability. Set the node's IP address, channel name, and channel port in the configuration file. During this configuration process, ensure that the following information is configured:

• bindnetaddr: Specifies the network interface address used for communication between nodes.
• mcastaddr: used to specify the multicast address.
• mcastport: used to specify the port number of the multicast channel.

totem { version: 2 secauth: off interface { ringnumber: 0 bindnetaddr: 192.168.50.0 mcastaddr: 226.94.1.1 mcastport: 5405 } transport: udpu } logging { to_logfile: yes logfile: /var/log/corosync/corosync.log to_syslog: yes }

In the heartbeat configuration file, you need to set the IP address and virtual IP address of the node. Make sure the application serving the virtual IP address is installed.

#设定hacluster集群名称 cluster hacluster #设定故障探测时间间隔 必须
        

         Copy after login
        
       

4. Configuring the cluster management tool

Install the pcs tool, which is a command line tool used to configure the Pacemaker cluster management software. It can be installed using the following command:

sudo yum install pcs sudo systemctl enable pcsd.service && sudo systemctl start pcsd.service

Configure the firewall to ensure that the firewall on any node allows communication. On CentOS7, you can use the following command:

sudo firewall-cmd --add-service=high-availability --permanent sudo firewall-cmd --reload

On each node, create the hacluster user and add it to the pcsd group for future management of the Pacemaker cluster:

sudo useradd hacluster sudo passwd hacluster sudo usermod -aG pcsd hacluster

To enable pcsd service, please use the following command:

sudo systemctl enable pcsd sudo systemctl start pcsd

Use the following command to configure authkey on Pacemaker and copy the authkey to all other nodes using the same options:

sudo pcs cluster auth   -u hacluster -p  --force

5. Configure Load Balancing

Install and configure HAproxy, which is a high-availability load balancing tool for TCP and HTTP applications. You can use the following command to install it on CentOS:

sudo yum -y install haproxy sudo systemctl enable haproxy

In the haproxy configuration file, you need to set the load balancing algorithm, the IP address and port number of the backend server.

global log 127.0.0.1 local2 chroot /var/lib/haproxy pidfile /var/run/haproxy.pid maxconn 4000 user haproxy group haproxy daemon # Enables HAProxy in daemon mode defaults log global mode http option httplog option dontlognull retries 3 option redispatch maxconn 2000 contimeout 5000 clitimeout 50000 srvtimeout 50000 frontend web bind *:80 mode http default_backend web-backend backend web-backend mode http balance roundrobin option httpchk HEAD / HTTP/1.1 Host:localhost server node1 10.0.0.2:80 check server node2 10.0.0.3:80 check

6. Test high availability architecture

Finally, test high availability. Disconnect one of the nodes and ensure that the virtual IP is automatically transferred to the other node. Confirm that applications on other nodes are running normally under the virtual IP to ensure high availability.

Conclusion

Deploying a high-availability architecture in Linux can ensure the stability and availability of enterprise applications in the face of unexpected failures. Using the HA architecture based on Corosync and Heartbeat, applications can be distributed to different server nodes through virtual IP addresses and load balancing algorithms to ensure their high availability and performance.

The above is the detailed content of How to deploy a high-availability architecture in Linux. For more information, please follow other related articles on the PHP Chinese website!